you have written a really informative,easy to read, and enjoyable essay. It is nice the way you have told your personal story from childhood to now and shown us your connection with space travel from early star gazing, SciFi., to employment and personal research of the subject alongside many snippets of fascinating factual information.
The radiotrophic fungi are something I have never heard about before. Life is amazing, and the idea of using them as a shield is ingenious. Also the ethylene connection to poor growth of plants in space. Such a simple solution. Couldn't some insect pollinated plants be hand pollinated as is often done in plant research facilities? It would give the astronauts something pleasant, maybe even stress relieving to do. And having some plants with showy flowers might also be a pleasant reminder of Earth's diversity of life.
I too think that mankind would have to take a self sufficient biosphere with him to colonize other worlds. Though I have suggested that we need to develop them and have them work reliably, and may actually need them on Earth, before taking the step into space. The ill fated biosphere II in mind. The way you have considered various hazards and how to overcome them begins to make it seem doable.
Good luck, Georgina